Using epithelial cells from primary human embryonic kidney cultures (HEK) and Madin-Darby canine kidney epithelial cells, we plan to study cell interactions with substrates composed of basement membrane components or of lectins. One of the basement membrane components we are investigating is laminin, which has been isolated from a transplantable mouse tumor in the laboratory of Dr. George Martin at N.I.H. We plan to elucidate the carbohydrate composition of laminin and investigate its interaction with various lectins. We will likewise characterize the surface of the epithelial cells with respect to which lectins they bind. We will then study the mechanism of binding of epithelial cells to laminin-coated substrates by trying to block binding with lectins which interact with laminin but not to the epithelial cells and vice versa. If we can find lectins which block cell binding to substrate, this will provide information about what kinds of carbohydrate moieties, either on the cell surface or on the laminin, are involved in the cell adhesion. We will then be able to see whether the adhesion can be blocked by appropriate oligosaccharide. We are also studying the adhesion of epithelial cells to substrates covered with lectins. These interactions will serve as models for studies on the adhesion of epithelial cells to basement membrane components.